According to the prior arts of exercisers, they basically comprise a frame assembly, a flywheel, a driving assembly and a power transmission mechanism. Reciprocation between the driving assembly and the flywheel is done through the power transmission mechanism. Inasmuch as the force applied by users is transmitted from the driving assembly, passed through the power transmission mechanism and then acted on the flywheel, the flywheel can be rotated correspondingly to the frame assembly. The prior arts of exercisers, used for increasing the workload of users to reach the goal of doing exercise, usually have a magnets adjusting device such as those disclosed in the U.S. Pat. No. 5,145,480, U.S. Pat. No. 5,310,392, U.S. Pat. No. 5,324,242, and U.S. Pat. No. 6,569,063. A magnets adjusting device mainly includes magnetic units and a movement control unit. The movement control unit can adjust the magnetic units to approach the flywheel and make the flywheel reciprocate with the magnetic units (so called cut across the magnetic field) to bear the resistance in order to achieve the objective of increasing workload for users.
Somehow, certain disadvantages from the design of the prior arts occur in their embodiments stated as below:
1. The mechanism of certain prior arts includes a slider with a U-shaped horizontal cross-section. There is a set of magnetic units on each side of the slider, and each set of the magnetic units is facing toward both sides of a flywheel. In order to avoid the inner surface of the slider contacting with the edge of the flywheel, either the moving range of the magnet units, corresponding to the flywheel, must be narrowed that it causes a disadvantage of reducing the adjusting range of resistance, or the size of the slider must be increased that it causes another disadvantage of increasing the production cost as well.
2. The mechanism of certain prior arts doesn't have a smoother sliding element. When the movement of the magnetic units is adjusted, it will cause disadvantages, such as inaccurate calculation of the resistance and damage of components, due to the unsmooth sliding.
3. The mechanism of certain prior arts is lack of a stable magnets adjusting device and a corresponding signal process unit. The resistance can not be accurately adjusted and displayed to meet users' need inasmuch as the variation of the resistance can not be effectively and accurately measured without a signal process unit.
Because the prior arts have above disadvantages and should be improved, the inventor of the present invention, with many years' experience of development on exercisers, devotes himself to experiment and improve prior designs. The present invention is made a better product to achieve the following objectives.